1. Field of the Invention
The invention relates to a drive roller for the rotational friction drive of a textile bobbin at a peripheral surface of a yarn package in a bobbin winder of a textile machine, wherein an active width of the driver roller is substantially less than a length of the bobbin.
When a bobbin is wound, the bobbin is either driven directly in a creel through its tube, or it rests on a friction drum with the peripheral surface of the yarn package and is entrained by the driven friction drum. If the drive of a bobbin is carried out by means of a friction drum, then the bobbin is always without any drive when it is lifted from the friction drum. A bobbin is always lifted from the friction drum once it is completely wound, or when a yarn break has occurred, or if a pay-out bobbin in a bobbin winding machine has run empty. Whenever the bobbin has been lifted from the friction drum, for instance because one end of the yarn is to be taken from a bobbin in order to splice the yarn, or because a yarn reserve is to be deposited on the tube next to the end surface of the bobbin, the bobbin has to be driven by a separate drive mechanism.
As a rule, the drive of a bobbin is performed by means of a driven drive roller, which presses against the peripheral surface of the yarn package, as is disclosed by German Published, Non-Prosecuted Application DE 35 43 572 A1. The width of such a drive roller is always substantially less than the length of a bobbin. The greater the volume of yarn on a bobbin, or in other words the greater the mass of the bobbin, the harder it is for the drive roller to accelerate such a bobbin from a standstill and then drive it. Especially in open-end spinning machines, in which paying out must be done from the spinning station at a specified pay-out speed that must not be below a certain minimum once the yarn has been pieced, it can become problematic to accelerate a heavy cross-wound bobbin. By increasing the contact pressure of a drive roller, the friction between the drive roller and the yarn package can be increased, and thus the acceleration can be improved.